The invention relates to an apparatus for folding into an open state sleeves which are lying flat and which consist of paper, cardboard or the like, and which comprise a longitudinal sealing seam, particularly for the manufacture of liquids packagings, and also a feeder for grasping the flat sleeve and introducing it into a position in which it is axially aligned between a mandrel and an ejector.
The invention is directed at all kinds of sleeves which are used in particular for producing packagings to contain flowing media, and by way of illustration and for better understanding, it will be described with reference to liquids packagings.
Packagings are already known for milk, juices and the like, which comprise a sleeve consisting of paper which is coated with a synthetic plastics material, one end of the sleeve being sealed by being folded into a rectangular bottom, the other and opposite end of the sleeve being provided with an integrally moulded lid with no carrier material, i.e. a pure synthetic plastics material. Here, sleeves in the form of a tube are known which have a substantially circular cross-section. Machines constructed to manufacture such packagings comprise at least one shaping wheel with a plurality of mandrels, firstly the sleeve being formed from a paper web (coated with synthetic plastics material) as a longitudinal sealing seam is formed, after which the sleeve is pushed onto the mandrel so that what will subsequently be the lid and which also includes the pouring means, can be injection moulded on at one end. The mandrel onto which the sleeve is pushed constitutes virtually the inner mould about which a two-part outer mould is placed so that the end of the sleeve can be so connected to the injection moulded synthetic plastics material that the packaging receives its lid which is integrally moulded on in fluid-tight fashion.
Liquids packagings of this type and also other forms of liquids packagings are used as disposable containers to an ever increasing extent by the end user and are therefore marketed. The corresponding filling machines and also packaging producing machines must have a relatively high output, i.e. for a given unit of time, more packagings must be produced and thus also more sleeves must be pushed onto mandrels and provided with end walls.
From the point of view of saving material, the trend has been to go over to thinner sleeve walls, so that handling of the sleeve and its processing in the packaging producing machine is certainly not simplified.
In the case of the aforementioned round package which has a rectangular bottom and a round lid, manufacture is carried out in a machine in which firstly the sleeve is offered in a lying-flat state after which it is passed via a feeder in between the mandrel and an ejector, the sleeve being opened up from the flat state into a circular cross-section. By reason of the circular cross-section, it is immaterial at which location on the periphery, seen in cross-section, the longitudinal sealing seam by which the flat sheet is formed into the sleeve, is disposed.
In the meantime, attempts have also been made to produce cross-sectionally rectangular liquids packagings, in which case sleeves are likewise used, being produced by the making of a longitudinal sealing seam, preferably a sealing seam having overlapping end portions.
With regard to the manufacture of the parallelepiped liquids packaging, the bottom is formed from the paper material itself by folding, while at the opposite end the lid is integrally moulded on in a rectangular shape and incorporates the pouring device. This latter is so disposed that the pouring tip, in a plan view of the packaging from the lid end, points to a corner thereof and is disposed in the vicinity thereof. On grounds of strength and so that the end user can readily grasp and handle the package, it has proved to be advantageous if the longitudinal sealing seam is disposed on the adjacent lateral folded edge in relation to the pouring orifice. In fact, one can easily imagine that the doubled-over marginal strip means that in the region of the longitudinal sealing seam the packaging is made more rigid. If, then, this rigid lateral fold edge is used as the point to which the end user applies his efforts, then this is the point at which the packaging bends least readily and where depressions or damage should be least feared when the packaging is grasped and gripped between the thumb and the other four fingers of the hand. Since the greatest pressure is applied to the packaging via the thumb (it is greater than the other four fingers' pressure), it is a good idea if the lateral seam of the packaging sleeve with the longitudinal sealing seam is so located that the pouring device in the lid is disposed at the top and transversely thereto so that during pouring the plane of the poured stream passes through those two lateral folded edges in the vicinity of one of which the tip of the pouring orifice is disposed while in the vicinity of the other of which the four fingers of the user are applied in order to pour out the contents, while the thumb is applied to the lateral fold edge of the sleeve which is disposed transversely thereto and which is reinforced by the longitudinal sealing seam.
If these considerations are taken into account where the manufacturing machine is concerned, then, particularly in the case of a packaging having a cross-sectionally rectangular shape, difficulties occur in that even with the high output of the packaging producing machine, it would be desirable to have the longitudinal sealing seam of the sleeve always on one specific edge of the mandrel. In other words, the feeder for gripping the lying-flat sleeve and also the measures and means of folding the sleeve open must be of such a configuration that the longitudinal sealing seam is always positioned at the desired location on the mandrel.
This consideration becomes particularly problematical when two shaping wheels are used at the same time, if sleeves have to be pushed onto two different mandrels one after the other and then, after the synthetic plastics lid has been moulded on, the packagings have to be brought into a row, filled, sealed and then carried away.
Also with packagings which are produced in such a way, the longitudinal sealing seams must always be in the same position.
Therefore, the inventor has set out to resolve the problem of so improving the apparatus for folding open sleeves of the aforesaid type which are lying flat that it is made possible with the new apparatus reliably to open out the lying-flat sleeve at a high working rate into a shape of rectangular cross-section, the longitudinal sealing seam always being in one specific position.